Arlington Embraces Housing Diversity with 'Missing Middle' Amendments.
Arlington, Virginia has become the first locality in the D.C. region to allow multiunit residential buildings across the county, ending its single-family-only zoning policy. The move will make it easier to build townhouses, duplexes, and small buildings with up to four or six units in neighborhoods that for decades required one house with a yard on each lot. The policy, which had prompted months of explosive debate, will make more "missing middle" housing available, an increasingly popular but often contested idea in urban planning.